This invention relates to article carriers and more particularly to panel interlocking arrangements for securing together the overlapped ends of wraparound type carrier blanks and is specially adapted to enhance package security in such carrier.
U.S. Pat. No. 4,077,095 issued Mar. 7, 1978 discloses panel interlocking arrangement for securing two overlapped panels. A locking tab having lateral projections is struck from one of the panels, and a retaining tab is struck from the other panel. The locking tab is driven through the locking aperture which is defined by the retaining tab, and thereby the retaining tab is folded out of the plane of the other panel. This causes the locking and retaining tabs to engage each other in angular mutually bracing relation. When the locking tab is driven through the aperture, a securing aperture formed in the base portion of the locking tab receives a securing tab projecting from an edge of the locking aperture. This enhances security of the lock.
New Zealand Patent 191646 issued Sep. 20, 1983 discloses another panel interlocking arrangement. The disclosed arrangement also includes a locking tab having lateral projections and a securing aperture for receiving a securing tab. The arrangement of this patent differs from the above U.S. patent in that it includes two retaining tabs which define a single locking aperture. Insertion of the locking tab into the aperture causes the lateral projections of the locking tab to respectively engage the free end edge of the two retaining tabs which have been folded due to the tab-inserting operation.
In each patent mentioned above, engagement between the securing aperture and the securing tab increases security of the lock on the panels. However, formation of the securing aperture in the locking tab decreases the stress in the locking tab which is induced by folding the locking tab during insertion. Such stress, due to the inherent resistance of the paperboard material from which the locking tab is struck, is important since it tends to urge the locking tab against the retaining tab. This is therefore believed to contribute to stable engagement between the locking and retaining tabs.
What is needed, therefore, is a new arrangement for securing two overlapped panels, wherein stability of engagement between the locking and retaining tabs is increased.